In mammals, including humans, adipocytes (fat cells) store excess energy in the form of triglycerides at times of nutritional excess (see Lowell, Cell, 99: 239-242, 1999). During starvation, stored triglycerides are degraded to fatty acids in adipocytes in order to supplement nutritional and energy requirements. Conditions in which excess adipose tissue accumulation, achieved either through recruitment of progenitor cells (pre-adipocytes) to become adipocytes (differentiation) and/or through expansion of the pre-existing adipocytes (hyperplasia and hypertrophy), leads to obesity and insulin resistance (see Lowell, Cell, 99: 239-242, 1999). Because, hypertrophied adipocytes (which are considered relatively less metabolically active) produce excessive amounts of fatty acids and cytokines which in turn act to reduce insulin signaling and glucose uptake in skeletal muscle and adipocytes, two major glucose utilizing tissues (see Hotamisligil, et al., Science, 259: 87-90, 1993; Lowell, Cell, 99: 239-242, 1999). Obese individuals frequently suffer from inadequate energy expenditure, high fat content in skeletal muscle, liver and plasma, insulin resistance, hypertension, atherosclerosis and cardiovascular diseases (see Rosenbaum et al., New. Eng. J. Med. 337: 396-407, 1997, see Friedman, Nature, 404: 632-634, 2000). Conditions such as seen in lipodystrophic syndrome patients with severely depleted fat depot leads to reduced body weight, increased lipid content in plasma, liver and skeletal muscle which in turn pre-dispose the patients to insulin resistance and Type 2 diabetes (see Arioglu et. al., Annals of Int. Med, 2000,133:263-274). The primary cause of these abnormalities appears to be due to relatively small amounts of adipose tissue available for safe storage of lipids.
Obesity is a common clinical problem in most developed nations and is also rapidly becoming a major health concern in developing nations. Overweight individuals frequently suffer from several metabolic disorders such as dyslipidemia, insulin resistance and Type 2 diabetes. These individuals also frequently suffer from hypertension, atherosclerosis and increased risk for cardiovascular diseases (see Friedman, Nature, 404: 632-634, 2000).
Peroxisome Proliferator Activated Receptors (PPARs) are members of the nuclear hormone receptor family of ligand regulated transcription factors (see Willson, et al., J. Med. Chem., 43: 527-550, 2000, Kersten et al., Nature, 405: 421424, 2000). Three PPAR isoforms, PPARγ, PPARα, and PPARδ have been isolated from various mammalian species including humans. These receptors, as a class, form obligate heterodimers with their binding partner RXRα, and are activated by diet derived long chain fatty acids, fatty acid metabolites and by synthetic agents (see Willson, et al., J. Med. Chem., 43: 527-550, 2000). It is now well documented that PPARs, through regulation of genes in glucose and lipid metabolism pathways, play a major role in maintaining glucose and lipid homeostasis in mammals including human.
PPARγ is a principal regulator of pre-adipocyte recruitment and differentiation into mature adipocytes and lipid accumulation in mature adipocytes (see Tontonoz et al., Current Biology, 571-576, 1995). Activators of PPARγ promote pre-adipocyte differentiation, lipid storage in mature adipocytes and act as insulin sensitizing anti-diabetic agents (see Tontonoz et al., Current Biology, 571-576, 1995; Lehmann et al., J. Biol. Chem., 270: 12953-12956, 1995; Nolan et al. New. Eng. J. Med., 331: 1188-1193; Inzucchi et al., New Eng. J. Med., 338: 867-872, 1998, Willson, et al., J. Med. Chem.: 43: 527-550, 2000, Kersten et al., Nature, 405: 421-424, 2000). The PPARγ induced anti-diabetic activity is however, frequently accompanied by some body weight gain in animal models and in humans. PPARγ expression is significantly elevated in the adipose tissue of obese individuals (see Vidal-Puig et al., J. Clinical Investigation, 99: 2416-2422, 1997), and a mutation which generated constitutively active PPARγ is associated with severe obesity (see Ristow et al., New England J. Med., 339:953-959, 1998). Partial loss of PPARγ expression leads to resistance to diet induced obesity in heterozygous PPARγ knock-out mice (see Kubota et al. Mol. Cell; 4:597-609, 1999) and lower body mass index in human with a proline to alanine change at amino acid position 12 (see Deeb et al Nature Genetics, 20:284-287, 1998). Relatively more severe loss of human PPARγ activity through dominant negative mutations, which abolish ligand binding to the receptor, leads to hyperlipidemia, fatty and liver insulin resistance, (see Barroso et al. Nature, 402, 860-861, 1999). The major cause of the abnormalities appears to be due to relatively small amounts of adipose tissue available for safe storage of lipids. These mouse and human findings show therefore, a role for PPARγ in the induction and or progression of obesity and suggest that inhibition of PPARγ will lead to a reduction in adiposity and obesity. These findings also suggest that such a reduction is likely to lead to higher plasma free fatty acids and hyperlipidemia and development fatty liver and insulin resistance
The PPARα isoform regulates genes in the fatty acid synthesis, fatty acid oxidation and lipid metabolism pathways (see Isseman and Green, Nature, 347: 645-649, 1990; Torra et al., Current Opinion in Lipidology, 10: 151-159, 1999; Kersten et al., Nature, 405: 421424, 2000). PPARα agonist (such as fenofibrate, gemfibrozil) treatment enhance fatty acid oxidation in the liver and muscle, reduce fatty acid and triglyceride synthesis in the liver and reduce plasma triglyceride levels (see Kersten et al., Nature, 405: 421424, 2000). In patients with high triglycerides and low HDL-cholesterol treatment with PPARα agonists lead to an increase in plasma HDL-cholesterol, decrease in plasma triglycerides and reduction in both primary and secondary cardiac events (see Balfour et al., Drugs. 40: 260-290, 1990; Rubins et al., New Eng. J. Med., 341: 410-418, 1999).
Therefore, by combining PPARγ antagonist activity and PPARα agonist activity in a single dual acting compound or in a formulation, it is possible to inhibit PPARγ and treat obesity without causing hyperlipidemia, fatty liver and insulin resistance. The present invention shows a novel method of treatment of obesity by combining two different activities, the PPARγ antagonist activity and PPARα agonist activity, to reduce adiposity and body weight without causing hyperlipidemia and insulin resistance. The invention proposes that the obese, hyperlipidemic and insulin resistant Type 2 diabetic patients can be treated with a dual PPARγ antagonist/PPARα agonist or a PPARγ antagonist and a PPARα agonist in combination with a lipid lowering agent and an anti-diabetic agent. The invention also provides a list of target genes wherein their expression is altered in adipose (fat) tissue through PPARγ antagonist activity to achieve anti-obesity, insulin sensitivity and cardiovascular disease benefits.
In accordance with the present invention, substituted acid derivatives are provided which have the structure I wherein
m is 0, 1 or 2; n is 0, 1 or 2;
Q is C or N
A is (CH2)x where x is 1 to 5; or A is (CH2)x1, where x1 is 2 to 5, with an alkenyl bond or an alkynyl bond embedded anywhere in the chain; or A is —(CH2)x2—O—(CH2)x3— where x2 is 0 to 5 and x3 is 0 to 5, provided that at least one of x2 and x3 is other than 0,
X1 is CH or N
X2 is C, N, O or S;
X3 is C, N, O or S;
X4 is C, N, O or S, provided that at least one of X2, X3 and X4 is N;
X5 is C, N, O or S;
X6 is C or N;
X7 is C, N, O or S, provided that at least one of X5, X6 or X7 is N.
In each of X1 through X7, as defined above, C may include CH.
R1 is H or alkyl;
R2 is H, alkyl, alkoxy, halogen, amino or substituted amino;
R2a, R2b and R2c may be the same or different and are selected from H, alkyl, alkoxy, halogen, amino or substituted amino;
R3 and R3a are the same or different and are independently selected from H, alkyl, arylalkyl, aryloxycarbonyl, alkyloxycarbonyl, alkynyloxycarbonyl, alkenyloxycarbonyl, arylcarbonyl, alkylcarbonyl, aryl, heteroaryl, cycloheteroalkyl, heteroarylcarbonyl, heteroaryl-heteroarylalkyl, alkylcarbonylamino, arylcarbonylamino, heteroarylcarbonylamino, alkoxycarbonylamino, aryloxycarbonylamino, heteroaryloxycarbonylamino, heteroaryl-heteroarylcarbonyl, alkylsulfonyl, alkenylsulfonyl, heteroaryloxycarbonyl, cycloheteroalkyloxycarbonyl, heteroarylalkyl, aminocarbonyl, substituted aminocarbonyl, alkylaminocarbonyl, arylaminocarbonyl, heteroarylalkenyl, cycloheteroalkyl-heteroarylalkyl; hydroxyalkyl, alkoxy, alkoxyaryloxycarbonyl, arylalkyloxycarbonyl, alkylaryloxycarbonyl, arylheteroarylalkyl, arylalkylarylalkyl, aryloxyarylalkyl, haloalkoxyaryloxycarbonyl, alkoxycarbonylaryloxycarbonyl, aryloxyaryloxycarbonyl, arylsulfinylarylcarbonyl, arylthioarylcarbonyl, alkoxycarbonylaryloxycarbonyl, arylalkenyloxycarbonyl, heteroaryloxyarylalkyl, aryloxyarylcarbonyl, aryloxyarylalkyloxycarbonyl, arylalkenyloxycarbonyl, arylalkylcarbonyl, aryloxyalkyloxycarbonyl, arylalkylsulfonyl, arylthiocarbonyl, arylalkenylsulfonyl, heteroarylsulfonyl, arylsulfonyl, alkoxyarylalkyl, heteroarylalkoxycarbonyl, arylheteroarylalkyl, alkoxyarylcarbonyl, aryloxyheteroarylalkyl, heteroarylalkyloxyarylalkyl, arylarylalkyl, arylalkenylarylalkyl, arylalkoxyarylalkyl, arylcarbonylarylalkyl, alkylaryloxyarylalkyl, arylalkoxycarbonylheteroarylalkyl, heteroarylarylalkyl, arylcarbonylheteroarylalkyl, heteroaryloxyarylalkyl, arylalkenylheteroarylalkyl, arylaminoarylalkyl, aminocarbonylarylarylalkyl;
Y is CO2R4 (where R4 is H or alkyl, or a prodrug ester) or Y is a C-linked 1-tetrazole, a phosphinic acid of the structure P(O)(OR4a)R5, (where R4a is H or a prodrug ester, R5 is alkyl or aryl) or a phosphonic acid of the structure P(O)(OR4a)2;
(CH2)x, (CH2)x1, (CH2)x1, (CH2)x3, (CH2)m, and (CH2)n may be optionally substituted with 1, 2 or 3 substituents;
including all stereoisomers thereof, prodrug esters thereof, and pharmaceutically acceptable salts thereof.
Preferred are compounds of formula I of the invention having the structure IA 
More preferred are compounds of formula I of the invention having the structures IB 
In the above compounds, it is most preferred that R2a, R2b and R2c are each H; R1 is alkyl, preferably CH3; x2 is 1 to 3 and x3 is 0; R2 is H; m is 0 or (CH2)m is CH2 or CHOH or CH-alkyl, X2, X3, and X4 represent a total of 1, 2 or 3 nitrogens; (CH2)n is a bond or CH2; R3 is aryl, arylalkyl or heteroaryl such as thiophene or thiazole, most preferably phenyl or phenyl substituted with alkyl, polyhaloalkyl, halo, alkoxy, preferably CF3 and CH3, R3a is preferably H or alkyl.
Preferred compounds of the invention include the following: 
The present invention describes the discovery of dual PPARγ antagonist/PPARα agonist activity in a single molecule. The invention shows that administration of a dual PPARγ antagonist/PPARα agonist to severely diabetic, hyperlipidemic and obese db/db mice leads to a reduction in plasma triglycerides and free fatty acid levels, without a change in glucose levels. The present invention shows that administration of a dual PPARγ antagonist/PPARα agonist to a diet-induced obese mice leads to reduced body fat content and reduced fat in liver without inducing hyperlipidemia and or insulin resistance. The invention provides a list of target genes wherein their expression is altered in adipose (fat) tissue through PPARγ antagonist activity to achieve anti-obesity, insulin sensitivity and cardiovascular disease benefits.
Accordingly, one object of the present invention is to provide a novel method for treating obesity in a mammal, including human, comprising administering to the mammal in need of such treatment a therapeutically effective amount of a single compound or combination of compounds that simultaneously inhibits PPARγ and activates PPARα.
Another object of the present invention provides a method for treating metabolic syndrome (obesity, insulin resistance and dyslipidemia) in a mammal, including a human, comprising administering to the mammal in need of such treatment, a therapeutically effective amount of any combination of two or more of the following compounds: a compound or combination of compounds that antagonize PPARγ, activates PPARα activity, an anti-diabetic compound such as but not limited to insulin, metformin, insulin sensitizers, sulfonylureas, aP2 inhibitor, SGLT-2 inhibitor, a lipid-lowering agent such as but not limited to statins, fibrates, niacin ACAT inhibitors, LCAT activators, bile acid sequestering agents and a weight reduction agent such as but not limited to orlistat, sibutramine, aP2 inhibitor, adiponectin.
Another object of the present invention is to provide a list of target genes (such as HMGic, glycerol-3-PO4-dehydrogenase, G-protein coupled receptor 26, fatty acid transport protein, adipophilin and keratinocyte fatty acid binding protein) whose expression can be altered to obtain anti-obesity effects through administration of a PPARγ antagonist and dual PPARγ antagonist/PPARα agonist or through other methods.
Another object of the present invention is to provide a list of target genes (such as PAI-1, Renin, angiotensinogen precursor) whose expression can be altered to obtain beneficial effects against cardiovascular diseases through administration of a PPARγ antagonist and dual PPARγ antagonist/PPARα agonist or through other methods.
Another object of the present invention provides a pharmaceutical composition for the treatment of obesity comprising: a pharmaceutically acceptable carrier and a therapeutically effective amount of a compound or combination of compounds that simultaneously inhibits PPARγ and activates PPARα.
Another object of the present invention provides a pharmaceutical composition for the treatment of obesity, insulin resistance and/or dyslipidemia, comprising: a pharmaceutically acceptable carrier and a therapeutically effective amount of a compound or combination of compounds that simultaneously inhibits PPARγ and activates PPARα and an anti-diabetic compound, a lipid-lowering agent and a weight reduction agent.
In addition, in accordance with the present invention, a method is provided for treating diabetes, especially Type 2 diabetes, and related diseases such as insulin resistance, hyperglycemia, hyperinsulinemia, elevated blood levels of fatty acids or glycerol, hyperlipidemia, obesity, hypertriglyceridemia, inflammation, Syndrome X, diabetic complications, dysmetabolic syndrome, atherosclerosis, and related diseases wherein a therapeutically effective amount of a compound of structure I is administered to a patient in need of treatment.
In addition, in accordance with the present invention, a method is provided for treating early malignant lesions (such as ductal carcinoma in situ of the breast and lobular carcinoma in situ of the breast), premalignant lesions (such as fibroadenoma of the breast and prostatic intraepithelial neoplasia (PIN), liposarcomas and various other epithelial tumors (including breast, prostate, colon, ovarian, gastric and lung), irritable bowel syndrome, Crohn's disease, gastric ulceritis, and osteoporosis and proliferative diseases such as psoriasis, wherein a therapeutically effective amount of a compound of structure I is administered to a patient in need of treatment.
In addition, in accordance with the present invention, a method is provided for treating diabetes and related diseases as defined above and hereinafter, wherein a therapeutically effective amount of a combination of a compound of structure I and another type antidiabetic agent and/or a hypolipidemic agent, and/or lipid modulating agent and/or other type of therapeutic agent, is administered to a human patient in need of treatment.
In the above method of the invention, the compound of structure I will be employed in a weight ratio to the antidiabetic agent (depending upon its mode of operation) within the range from about 0.01:1 to about 100:1, preferably from about 0.5:1 to about 10:1.
The conditions, diseases, and maladies collectively referenced to as “Syndrome X” or Dysmetabolic Syndrome (as detailed in Johanson, J. Clin. Endocrinol. Metab., 1997, 82, 727-734, and other publications) include hyperglycemia and/or prediabetic insulin resistance syndrome, and is characterized by an initial insulin resistant state generating hyperinsulinemia, dyslipidemia, and impaired glucose tolerance, which can progress to Type II diabetes, characterized by hyperglycemia, which can progress to diabetic complications.
The term “diabetes and related diseases” refers to Type II diabetes, Type I diabetes, impaired glucose tolerance, obesity, hyperglycemia, Syndrome X, dysmetabolic syndrome, diabetic complications and hyperinsulinemia.
The conditions, diseases and maladies collectively referred to as “diabetic complications” include retinopathy, neuropathy and nephropathy, and other known complications of diabetes.
The term “other type(s) of therapeutic agents” as employed herein refers to one or more antidiabetic agents (other than compounds of formula I), one or more anti-obesity agents, and/or one or more lipid-lowering agents, one or more lipid modulating agents (including anti-atherosclerosis agents), and/or one or more antiplatelet agents, one or more agents for treating hypertension, one or more anti-cancer drugs, one or more agents for treating arthritis, one or more anti-osteoporosis agents, one or more anti-obesity agents, one or more agents for treating immunomodulatory diseases, and/or one or more agents for treating anorexia nervosa.
The term “lipid-modulating” agent as employed herein refers to agents which lower LDL and/or raise HDL and/or lower triglycerides and/or lower total cholesterol and/or other known mechanisms for therapeutically treating lipid disorders.